The diploma thesis analyses the influence of lighting conditions on the colour capture and perception of building facades in the historic city centre of Maribor. The aim of the research was to determine the extent to which the difference between direct sunlight and shaded illumination affects the measured colour values of facades, and to examine whether the camera focus method influences the calculated colour difference. Measurements were carried out on 22 selected objects in the historic city centre. Photographs were captured using an Apple iPhone 17 Pro smartphone in RAW format, which preserves the original sensor data without irreversible colour corrections. Colour values were determined in the CIE L*a*b* colour space (CIELAB) using the colour sampling tool in Adobe Photoshop, calculated as the average of ten randomly selected measurement points on both the shaded and the sunlit side of each facade. For selected objects, additional photographs were taken with the camera focus set on the shaded or the sunlit part of the facade. The results showed that lighting conditions significantly affect the measured colour values of facades. The difference between the sunlit and shaded sides was most pronounced in the lightness component L*, which was substantially higher under direct sunlight for all measured objects. The chromatic components a* and b* were also higher under sunlit conditions, indicating more intense warm colour tones. The total colour difference ΔE*ab, calculated as the geometric distance between two points in colour space, ranged from 24.6 to 54.5 across the measured objects. Facades in the Maribor city centre generally exhibited warm colour tones with predominantly positive a* and b* values. It was found that the camera focus method influences the calculated colour difference: focusing on the shaded part of the facade tended to reduce the difference, while focusing on the sunlit part tended to increase it.
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